Hydration and microstructure evolution of a novel low-carbon concrete containing recycled clay brick powder and ground granulated blast furnace slag

Abstract

This study focuses on a novel low-carbon concrete containing recycled clay brick powder (RCBP) and ground granulated blast furnace slag (GGBFS). The effects of RCBP and GGBFS on hydration process and microstructure of the novel low-carbon concrete with different replacement levels ranging from 0 to 40% have been studied by testing workability, compressive strength, hydration heat, hydration products and pore structure. The incorporation of blended GGBFS and RCBP makes up for the excessive strength loss of concretes with high volume RCBP. Furthermore, RCBP and GGBFS can reduce the cumulative hydration heat and accelerate Portland cement hydration. Samples with RCBP and GGBFS have a lower portlandite content and a high hydration degree at 90 d. Meanwhile, RCBP-GGBFS has an excellent combined effect on optimizing the microstructure. Ultimately, the CO2 emission and cost of mixtures with RCBP and GGBFS are significantly reduced. This study is expected to help enhance the utilization efficiency of RCBP to produce the low-carbon building materials.